Quantifying the Impact of Groundwater Pollution on the Mortality Rate in the Central Valley of California

Communities around the country and worldwide are facing the burden of past environmental pollution and intensifying climate change. One area where these challenges intersect with socioeconomic disparity and racial diversity is the Central Valley of California.The Central Valley is known for its vast agricultural land which faces high levels of groundwater pollution leading to harmful nitrate concentrations in drinking water. Not all communities are similarly exposed to this pollution. Rural communities live closer to agrarian lands and benefit less from the regular monitoring of water quality in urban areas.

The goal of our study is to quantify the degree to which groundwater pollution affects child mortality in the Central Valley. We use preventable disease hospitalization rates as a metric for mortality, and pollution-related health impacts more generally. We obtain these hospitalization rates using Medicaid data. To measure groundwater contamination, we take advantage of the Groundwater Ambient Monitoring and Assessment (GAMA) dataset at the zip code level of wells in the Central Valley. Our work advances previous research that has used California Environmental Screen (CalEnviroScreen) to measure the effects of pollution on health.

A drawback of using broad indices like CalEnviroScreen is that policy-makers use these indices merely to characterize communities as more or less vulnerable using aggregate statistics without creating explicit links to what they are vulnerable to or why. By combining the GAMA dataset with Medicaid data, we attempt to create a link between environmental exposures and health outcomes. This helps us identify the communities that are most affected by adverse health outcomes. Policy-makers can design appropriate targeted programs that uplift and protect these marginalized communities through regulated and monitored wells. Policy to control this ongoing issue is important as communities with high poverty rates and racial minority populations continue to be at higher risk of pollution-related health complications.